I. Field
The present disclosure relates generally to wireless communications, and more specifically to techniques for resource allocation in a wireless communication system.
II. Background
Wireless communication systems are widely deployed to provide various communication services; for instance, voice, video, packet data, broadcast, and messaging services can be provided via such wireless communication systems. These systems can be multiple-access systems that are capable of supporting communication for multiple terminals by sharing available system resources. Examples of such multiple-access systems include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, and Orthogonal Frequency Division Multiple Access (OFDMA) systems.
Generally, a wireless multiple-access communication system can simultaneously support communication for multiple wireless terminals. In such a system, each terminal can communicate with one or more base stations via transmissions on the forward and reverse links. The forward link (or downlink) refers to the communication link from the base stations to the terminals, and the reverse link (or uplink) refers to the communication link from the terminals to the base stations. This communication link can be established via a single-in-single-out (SISO), multiple-in-single-out (MISO), or a multiple-in-multiple-out (MIMO) system.
Downlink communication in a wireless communication system can be conducted by a Node B or access point by transmitting information to a user equipment (UE) or terminal. In response to information transmitted to a UE on the downlink, the UE can respond with an acknowledgement (ACK) to the Node B on the uplink using ACK resources assigned to the UE by the Node B. Conventionally, however, allocation of ACK resources in a wireless communication system has involved significant overhead. For example, existing techniques provide that uplink ACK resources can be mapped to downlink communication resources, but this technique requires excessive overhead if relatively few UEs utilize a significant portion of the downlink resources. Alternatively, other existing techniques for allocation of ACK resources involve mapping such resources to control channels used for communication with respective UEs. However, this technique is ineffective for UEs that do not utilize a control channel for communication with a Node B, such as UEs communicating pursuant to a persistent resource assignment. Further complications arise when persistently-assigned UEs operate in a system with UEs that rely on respective control channels for their communication functionality. Thus, there is a need for low-overhead techniques for ACK allocation that support UEs that communicate based on persistent resource assignments.